Various U.S. patents have taught the concept of controlling the viscosity of organic liquids by the addition of various type polymers.
U.S. Pat. No. 3,366,430 teaches the gelling of organic liquids by the interaction of polar "associative bonds" which includes hydrogen bonding and "ionic cross linking". It is clear that the language of this patent limits this invention to gells. The instant invention is distinct from that cited in that the most preferred state is free of any said gel at ambient temperatures. This patent also teaches that these polymers "will generally be of the free radical addition type" (column 4, lines 5-7), since the preparation of polar polymers by Ziegler-Natta polymerization is difficult because "the polar groups required in the final polymer may interfere with the ionic catalyst used in the polymerization, [thus] it is usually necessary just to prepare the hydrocarbon polymer and then modify it to introduce the polar groups required for this associative bond". (Column 4, lines 54-59). Once again the instant invention is a Ziegler-Natta polymer with attached functional group not post introduction of a functional group.
U.S. Pat. No. 4,002,436 teaches polymer solutions of associative bonds (esspecially jet fuel solutions). However, the polymers of the instant invention are distinct from those of U.S. Pat. No. 4,002,436.
The polymers used in U.S. Pat. No. 4,002,436, "will generally be of the free-radical addition type". (Column 4, line 16-18) since the preparation of polar polymers by Ziegler-Natta polymerization is difficult because "the polar groups required in the final polymer may interfere with the ionic catalyst used in the polymerization, [thus] it is usually necessary first to prepare the hydrocarbon polymer and then modify it to introduce the polar groups required for the associative bond". (Column 4, lines 60-64). The instant invention uses a Ziegler-Natta polymer with an attached functional group.
U.S. Pat. No. 3,679,382 teaches the thickening of aliphatic hydrocarbons with synthetic organic polymers of alkylstyrene or lauryl acrylate and olefinically unsaturated emulsion copolymerizable acids, amides, hydroxyacrylic esters, sulfonic acids, etc. It is emphasized in this patent (column 3, lines 69-75) that it is critical that in the preparation of such polymers, no surface active agent, catalyst or other additive be employed which introduces a metallic ion into the system. Therefore, it is preferred to employ ammonium or amine salts.
The instant invention contains no alkylstyrenes or lauryl acrylates and the instant olefinically unsaturated acids and esters are not emulsion copolymerizable. The instant acids and esters have an alkyl spacer group separating the acid or ester from the olefinic double bond thus rendering them now polymerizable by free radical emulsion polymerization. The instant copolymers are prepared by Ziegler-Natta polymerization, which do indeed use metallic catalysts. Such metallic species are precluded from U.S. Pat. No. 3,679,382.